高超声速飞行器上可调天线的设计与实现

当飞行器处于高超声速飞行状态时,其外部会形成等离子体鞘套。等离子体的存在会使飞行器上的天线发生阻抗失配,导致谐振频率偏移以及回波损耗的增加。通过不同速度、高度等条件下等离子体密度的数值预测,进一步估算对天线谐振频率偏移等性能的影响。考虑到元器件的电抗在L波段的寄生效应,利用广义连接网络的方法,对匹配网络设计和优化,完成等离子体环境下的天线阻抗调谐。实验表明,通过改变匹配网络中变容管的容值,等离子体环境下天线的输入阻抗可以被调节,从而复原谐振频率、降低回波损耗、恢复通信性能。

Design and implementation of tunable antenna on the hypersonic velocity aircraft

When the aircraft is in hypersonic velocity flight state, plasma sheath will be formed outside the aircraft. The existence of the plasma will cause impedance mismatch of the antenna on the aircraft, resulting in the resonance frequency effset and the increase of return loss. Through the numerical prediction of plasma density at different speeds, heights and other conditions, the influence of antenna resonance frequency offset and other performance is further estimated. Considering the parasitic effect of reactance of the components in L-band, the generalized connection network method is used to design and optimize the matching network for completing the antenna impedance tuning in plasma environment. The experimental results show that the input impedance of the antenna can be adjusted by changing the volume of the varactor in the matching network, which can restore the resonant frequency, return loss and communication performance.